Better have someone who actually have done it before I try it out. Region changed 3DSes doesn't boot until SecureInfo_A has been modified. Anyway, thanks for the reply.
Well, I can confirm that it works on Korean Consoles too. I A9LHed my friend's Korean 2DS. And as a Korean I saw many people succeeding on Korean Forums. As for the CTR thing, yup. Just choose one. It works.